Technical Field
Embodiments disclosed herein are related to Integrated-OCT-Refractometer systems. In more detail, embodiments are related to eye-visualization systems, Optical Coherence Tomographic (OCT) imaging systems, and refractometers to determine refractive characteristics of the eye based on the OCT image and a refractive mapping.
Related Art
Current ophthalmic refractive surgical methods, such as cataract surgery, intra-corneal inlays, Laser-Assisted in situ Keratomileusis (LASIK), and photorefractive keratectomy (PRK), rely on ocular biometry data to prescribe the best refractive correction. Historically, ophthalmic surgical procedures used ultrasonic biometry instruments to image portions of the eye. In some cases these biometric instruments generated an A-scan of the eye: an acoustic echo signal from all interfaces along an imaging axis that was typically aligned with an optical axis of the eye: either parallel with it, or making only a small angle. Other instruments generated a B-scan, essentially assembling a collection of A-scans, taken successively as a head or tip of the biometry instrument was scanned along a scanning line. This scanning line was typically lateral to the optical axis of the eye. These ultrasonic A- or B-scans were then used to measure and determine biometry data, such as an ocular Axial Length, an Anterior Depth of the eye, or the radii of corneal curvature. Examples of such ultrasonic ocular biometry devices include the Alcon UltraScan and Alcon OcuScan RxP.
In some surgical procedures a second, separate keratometer was used to measure refractive properties and data of the cornea. The ultrasonic measurements and the refractive data were then combined in a semi-empirical formula to calculate the characteristics of the optimal Intra Ocular Lens (IOL) to be prescribed and inserted during the subsequent cataract phaco surgery.
More recently, the ultrasonic biometry devices have been rapidly giving way to optical imaging and biometry instruments that are built on the principle of Optical Coherence Tomography (OCT). Examples include the Zeiss IOL Master and the Haag-Streit Lenstar. Such OCT instruments are now used in 80-90% of all IOL prescription cases. Among others, their success is due to the non-contact nature of the imaging and to the higher precision than that of the ultrasound biometers.
Even with these recent advances, however, substantial further growth and development is needed for the functionalities of the biometric and imaging instruments.